3 ms·
0-4 shift not 0-3? That is a little bit weird.
by brucehoult 2y ago
0-4 shift not 0-3? That is a little bit weird.
- phire 2y agoArm64 has fast 128-bit loads. Not just with NEON, but with regular integer instructions, you can quickly load 128 bits into a pair of 64-bit registers. So it kind of makes sense to support fast shift by four. Though, it's more likely they just profiled a bunch of code and decided fast shifts by four was worth budgeting for.